Communities of sheltered Mediterranean lower mediolittoral rock

This habitat develops on the lower horizon of mediolittoral rock in areas sheltered from wave action and currents although some of the associated species may also thrive on moderately exposed shores. The rock surfaces are dominated by algae, the characteristic species depending on the local conditions. In areas of gently almost horizontal slopes, the red algae Ceramium ciliatum can form an almost continuous carpet. There may be distinctive crusts of the brown algae Nemoderma tingitatum on the smooth rocky shores where there is moderate to low wave action, and in nutrient enriched areas the green algae of the genus Ulva dominates and may exclude settlement of other species of algae.

Indicators of quality:
The only biotope which might be sensitive to pollution and man-induced impacts is that dominated by Nemoderma tingitanum. Reduction in the total percent cover of this species and overall species richness can indicate a decrease on ecological quality. Both the biotopes of Ceramium ciliatum and Ulva spp. show extraordinary resilience to environmental impacts and they appear even in degraded environments. A "Quality of Rocky Bottoms index" (CFR by its Spanish acronym) used in Spanish Atlantic waters for the assessment of macroalgae communities on rocky shores may have some potentially application in assessment of quality of this habitat.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats